feat(nudges): Phase 6 — Margot soft-touch nudges via frontend nudge bus

Frontend-owned nudge bus that consumes in-app signals Corbie already
produces, applies suppression, and fans out to OS notification + an
optional TTS read-aloud. OS-wide keyboard/window activity detection
stays deferred per the revised roadmap — the plan before rewrite
would have been brittle on Wayland, permission-heavy on macOS, and
low-quality everywhere.

Triggers (v1, all in-app signals):
- inactivity_with_active_timer — timer running, window blurred ≥ 90 s,
  at least 60 s into the timer.
- pending_morning_triage — ritual enabled, past 10:00 local, last
  shown ≠ today. Polls every 5 min while focused.
- micro_step_idle — micro-step decomposition created, no child step
  or parent task completed within 15 min.

Suppression:
- Respects nudgesEnabled + nudgesMuted.
- No nudge while the app has focus (document.hasFocus).
- Hard cap 3 per rolling hour.
- Permission requested via @tauri-apps/plugin-notification on first
  delivery; denial is silently respected.

Rust side:
- tauri-plugin-notification registered + ACL entries on the main-
  window capability only (secondary windows can't fire nudges).
- commands::nudges::deliver_nudge — thin wrapper, security-guarded
  via ensure_main_window, delegates to the plugin. No DB writes —
  the roadmap's nudges-audit table is deferred until a concrete need
  emerges.

Frontend glue:
- nudgeBus.svelte.ts — subscribes to window events, applies
  suppression, calls deliver_nudge (+ tts_speak when speakAloud is
  on).
- kon:task-completed now dispatched on complete_task_cmd success.
- kon:microstep-generated + kon:step-completed dispatched from
  MicroSteps so the idle trigger can clear itself on any engagement.
- kon:focus-timer-cancelled added to focusTimer so the bus can reset
  its inactivity state on cancel, not only on natural completion.
- nudgeBus started from +layout.svelte onMount, stopped on destroy.

Settings:
- New "Nudges" section with three toggles: Enable nudges, Mute for
  now (separate so a hard mute doesn't lose preferences),
  Speak nudges aloud (reuses Phase 4 TTS).
- All default OFF. No first-run prompt — nudges are a Settings-found
  feature rather than a walkthrough step.

Out of scope per the revised Phase 6 spec: OS-wide keyboard/window
hooks, biometric signals, custom trigger editor (Phase 7), notification
sound (platform variance too high for Layer-1 — revisit in Phase 9
polish with a bundled .wav).

Gates: fmt clean, clippy -D warnings clean, cargo test 262/0 (4
existing + 262 current), npm run check 0/0, npm run build green.

Cargo.lock

@@ -2531,10 +2531,12 @@ dependencies = [
 
 [[package]]
 name = "js-sys"
-version = "0.3.85"
+version = "0.3.95"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8c942ebf8e95485ca0d52d97da7c5a2c387d0e7f0ba4c35e93bfcaee045955b3"
+checksum = "2964e92d1d9dc3364cae4d718d93f227e3abb088e747d92e0395bfdedf1c12ca"
 dependencies = [
+ "cfg-if",
+ "futures-util",
  "once_cell",
  "wasm-bindgen",
 ]
@@ -2599,6 +2601,7 @@ dependencies = [
  "tauri-plugin-autostart",
  "tauri-plugin-dialog",
  "tauri-plugin-global-shortcut",
+ "tauri-plugin-notification",
  "tauri-plugin-opener",
  "tauri-plugin-window-state",
  "tokio",
@@ -2909,6 +2912,18 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c41e0c4fef86961ac6d6f8a82609f55f31b05e4fce149ac5710e439df7619ba4"
 
+[[package]]
+name = "mac-notification-sys"
+version = "0.6.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "29a16783dd1a47849b8c8133c9cd3eb2112cfbc6901670af3dba47c8bbfb07d3"
+dependencies = [
+ "cc",
+ "objc2",
+ "objc2-foundation",
+ "time",
+]
+
 [[package]]
 name = "mach2"
 version = "0.5.0"
@@ -3187,6 +3202,20 @@ dependencies = [
  "windows-sys 0.52.0",
 ]
 
+[[package]]
+name = "notify-rust"
+version = "4.16.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5e551a9f0db223eaf3eb156906f99f46897fd951ee66dd1cb0be14db4d36d2fa"
+dependencies = [
+ "futures-lite",
+ "log",
+ "mac-notification-sys",
+ "serde",
+ "tauri-winrt-notification",
+ "zbus",
+]
+
 [[package]]
 name = "notify-types"
 version = "1.0.1"
@@ -3867,7 +3896,7 @@ checksum = "740ebea15c5d1428f910cd1a5f52cebf8d25006245ed8ade92702f4943d91e07"
 dependencies = [
  "base64 0.22.1",
  "indexmap 2.14.0",
- "quick-xml",
+ "quick-xml 0.38.4",
  "serde",
  "time",
 ]
@@ -3914,9 +3943,9 @@ dependencies = [
 
 [[package]]
 name = "portable-atomic"
-version = "1.13.0"
+version = "1.13.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f89776e4d69bb58bc6993e99ffa1d11f228b839984854c7daeb5d37f87cbe950"
+checksum = "c33a9471896f1c69cecef8d20cbe2f7accd12527ce60845ff44c153bb2a21b49"
 
 [[package]]
 name = "portable-atomic-util"
@@ -4056,6 +4085,15 @@ version = "2.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a993555f31e5a609f617c12db6250dedcac1b0a85076912c436e6fc9b2c8e6a3"
 
+[[package]]
+name = "quick-xml"
+version = "0.37.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "331e97a1af0bf59823e6eadffe373d7b27f485be8748f71471c662c1f269b7fb"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "quick-xml"
 version = "0.38.4"
@@ -5738,6 +5776,25 @@ dependencies = [
  "thiserror 2.0.18",
 ]
 
+[[package]]
+name = "tauri-plugin-notification"
+version = "2.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "01fc2c5ff41105bd1f7242d8201fdf3efd70749b82fa013a17f2126357d194cc"
+dependencies = [
+ "log",
+ "notify-rust",
+ "rand 0.9.4",
+ "serde",
+ "serde_json",
+ "serde_repr",
+ "tauri",
+ "tauri-plugin",
+ "thiserror 2.0.18",
+ "time",
+ "url",
+]
+
 [[package]]
 name = "tauri-plugin-opener"
 version = "2.5.3"
@@ -5875,6 +5932,18 @@ dependencies = [
  "toml 0.9.12+spec-1.1.0",
 ]
 
+[[package]]
+name = "tauri-winrt-notification"
+version = "0.7.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0b1e66e07de489fe43a46678dd0b8df65e0c973909df1b60ba33874e297ba9b9"
+dependencies = [
+ "quick-xml 0.37.5",
+ "thiserror 2.0.18",
+ "windows 0.61.3",
+ "windows-version",
+]
+
 [[package]]
 name = "tempfile"
 version = "3.27.0"
@@ -6598,9 +6667,9 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen"
-version = "0.2.108"
+version = "0.2.118"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "64024a30ec1e37399cf85a7ffefebdb72205ca1c972291c51512360d90bd8566"
+checksum = "0bf938a0bacb0469e83c1e148908bd7d5a6010354cf4fb73279b7447422e3a89"
 dependencies = [
  "cfg-if",
  "once_cell",
@@ -6611,23 +6680,19 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-futures"
-version = "0.4.58"
+version = "0.4.68"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "70a6e77fd0ae8029c9ea0063f87c46fde723e7d887703d74ad2616d792e51e6f"
+checksum = "f371d383f2fb139252e0bfac3b81b265689bf45b6874af544ffa4c975ac1ebf8"
 dependencies = [
- "cfg-if",
- "futures-util",
  "js-sys",
- "once_cell",
  "wasm-bindgen",
- "web-sys",
 ]
 
 [[package]]
 name = "wasm-bindgen-macro"
-version = "0.2.108"
+version = "0.2.118"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "008b239d9c740232e71bd39e8ef6429d27097518b6b30bdf9086833bd5b6d608"
+checksum = "eeff24f84126c0ec2db7a449f0c2ec963c6a49efe0698c4242929da037ca28ed"
 dependencies = [
  "quote",
  "wasm-bindgen-macro-support",
@@ -6635,9 +6700,9 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-macro-support"
-version = "0.2.108"
+version = "0.2.118"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5256bae2d58f54820e6490f9839c49780dff84c65aeab9e772f15d5f0e913a55"
+checksum = "9d08065faf983b2b80a79fd87d8254c409281cf7de75fc4b773019824196c904"
 dependencies = [
  "bumpalo",
  "proc-macro2",
@@ -6648,9 +6713,9 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-shared"
-version = "0.2.108"
+version = "0.2.118"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1f01b580c9ac74c8d8f0c0e4afb04eeef2acf145458e52c03845ee9cd23e3d12"
+checksum = "5fd04d9e306f1907bd13c6361b5c6bfc7b3b3c095ed3f8a9246390f8dbdee129"
 dependencies = [
  "unicode-ident",
 ]
@@ -6717,9 +6782,9 @@ dependencies = [
 
 [[package]]
 name = "web-sys"
-version = "0.3.85"
+version = "0.3.95"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "312e32e551d92129218ea9a2452120f4aabc03529ef03e4d0d82fb2780608598"
+checksum = "4f2dfbb17949fa2088e5d39408c48368947b86f7834484e87b73de55bc14d97d"
 dependencies = [
  "js-sys",
  "wasm-bindgen",