core: extract the store and sync engine into a shared crate (M12 step 1)

Android becomes a native Kotlin client over this same code (Scribe note 2730), so
the local store and sync engine stop being modules of the desktop app and become
`thoughtsync-core`, a crate with no UI framework in it at all.

This is a move, not a rewrite, and the measurement is why: every file in local/
and sync/ already carried ZERO Tauri references — 4,980 of 6,372 lines. The
coupling was 473 lines of command shim, which stays behind in the desktop crate
as src/commands/. Kept as git renames so history follows the files.

The desktop imports them under their old names (`use thoughtsync_core::{local,
sync}`) so every call site reads exactly as before. What moved is where they
live, not what they are.

Two things a workspace changes that are easy to miss, both caught before pushing:

[profile.release] now lives at the workspace ROOT. Cargo silently ignores
profiles declared by a non-root member — leaving it in the desktop crate would
have dropped lto/strip/opt-level from every release build with only a warning.

And a workspace shares ONE target dir, so the bundles moved from
desktop/src-tauri/target to target/. Thirteen references across publish-release,
debundle-graphics, verify.sh, package-prebuilt and the workflow now point there.
Pinning target-dir back would have been the smaller diff, but the Android lane
also produces Rust artifacts and they do not belong under desktop/.

Also retires the Tauri Android lane in the same push rather than leaving a path
that is being replaced: gen/android, android.yml and docs/android-dev.md are
gone, the mobile_entry_point attribute with them, and the lib drops to rlib —
staticlib/cdylib existed for Tauri mobile, and the .so Android loads will be
built from the core crate instead. Rule 22, no parallel path.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

core/src/local/models.rs

@@ -0,0 +1,182 @@
+//! Serde shapes for the local store. Output structs mirror the JSON the frontend
+//! already consumes (frontend/src/stores/*.ts) so the same components render whether
+//! the data comes from REST or from these Tauri commands. Field names/optionality
+//! match the TypeScript interfaces exactly.
+
+use serde::{Deserialize, Serialize};
+
+#[derive(Serialize)]
+pub struct Note {
+    pub id: String,
+    pub title: Option<String>,
+    /// title if set, else the note's first body line — always present, so body-only
+    /// notes are still nameable and `[[link]]`-able. Derived, never stored.
+    pub display_title: String,
+    pub body: String,
+    pub color: String,
+    pub kind: String,
+    pub position: i64,
+    pub pinned: bool,
+    pub archived: bool,
+    pub trashed: bool,
+    /// When it was trashed (null unless trashed). Named for the server's field so the
+    /// shared frontend counts down the retention window identically either way.
+    pub deleted_at: Option<String>,
+    pub remind_at: Option<String>,
+    pub recurrence: Option<String>,
+    pub labels: Vec<NoteLabel>,
+    pub items: Vec<ChecklistItem>,
+    pub attachments: Vec<Attachment>,
+    pub previews: Vec<LinkPreview>,
+    pub created_at: Option<String>,
+    pub updated_at: Option<String>,
+}
+
+#[derive(Serialize)]
+pub struct NoteLabel {
+    pub id: String,
+    pub name: String,
+    pub color: String,
+    /// True when attached because of a `#tag` in the body (kept in sync with the text).
+    pub via_tag: bool,
+}
+
+#[derive(Serialize)]
+pub struct ChecklistItem {
+    pub id: String,
+    pub text: String,
+    pub checked: bool,
+    pub position: i64,
+}
+
+#[derive(Serialize)]
+pub struct Attachment {
+    pub id: String,
+    pub url: String,
+    pub filename: Option<String>,
+    pub mime: String,
+    pub size: Option<i64>,
+    pub sha256: Option<String>,
+}
+
+#[derive(Serialize)]
+pub struct LinkPreview {
+    pub id: String,
+    pub url: String,
+    pub title: Option<String>,
+    pub description: Option<String>,
+    pub image_url: Option<String>,
+    pub site_name: Option<String>,
+}
+
+#[derive(Serialize)]
+pub struct NoteRevision {
+    pub id: String,
+    pub title: Option<String>,
+    pub body: String,
+    pub created_at: Option<String>,
+}
+
+#[derive(Serialize)]
+pub struct Label {
+    pub id: String,
+    pub name: String,
+    pub color: String,
+    // Note count is only meaningful in listings; omitted elsewhere so the frontend
+    // preserves the count it already holds (matches the REST single-label responses).
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub count: Option<i64>,
+}
+
+#[derive(Serialize)]
+pub struct TitleEntry {
+    pub id: String,
+    pub title: String,
+}
+
+#[derive(Serialize)]
+pub struct Backlink {
+    pub id: String,
+    pub title: String,
+}
+
+#[derive(Serialize)]
+pub struct SavedFilter {
+    pub id: String,
+    pub name: String,
+    /// Mirrors NoteFacets — stored as a JSON blob, round-tripped opaquely.
+    pub params: serde_json::Value,
+    pub position: i64,
+}
+
+#[derive(Serialize)]
+pub struct PublicConfig {
+    pub site_name: String,
+    pub allow_registration: bool,
+    pub version: String,
+    pub enable_url_unfurl: bool,
+    pub trash_retention_days: u32,
+}
+
+/// The synthetic single user the offline core reports, so the app's auth-gated
+/// router resolves without a login. There is no real account offline.
+#[derive(Serialize)]
+pub struct User {
+    pub id: String,
+    pub email: String,
+    pub display_name: String,
+    pub email_verified: bool,
+    pub is_admin: bool,
+}
+
+fn default_color() -> String {
+    "default".to_string()
+}
+
+#[derive(Deserialize)]
+pub struct NoteCreateInput {
+    #[serde(default)]
+    pub title: String,
+    #[serde(default)]
+    pub body: String,
+    #[serde(default = "default_color")]
+    pub color: String,
+    #[serde(default)]
+    pub kind: Option<String>,
+    #[serde(default)]
+    pub items: Option<Vec<String>>,
+}
+
+/// The board query (mirrors adapters/repo.ts NoteListQuery). `labelId` is camelCase
+/// on the wire; the facet fields are snake_case, matching NoteFacets.
+#[derive(Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct ListQuery {
+    pub view: String,
+    #[serde(default)]
+    pub label_id: Option<String>,
+    #[serde(default)]
+    pub facets: Option<Facets>,
+    #[serde(default)]
+    pub sort: Option<String>,
+}
+
+#[derive(Deserialize)]
+pub struct Facets {
+    #[serde(default)]
+    pub q: Option<String>,
+    #[serde(default)]
+    pub color: Option<String>,
+    #[serde(default)]
+    pub kind: Option<String>,
+    #[serde(default)]
+    pub label: Option<Vec<String>>,
+    #[serde(default)]
+    pub has_reminder: Option<bool>,
+    #[serde(default)]
+    pub has_attachment: Option<bool>,
+    #[serde(default)]
+    pub created_after: Option<String>,
+    #[serde(default)]
+    pub created_before: Option<String>,
+}