refactor(persistence): split persistence.rs into domain modules behind a barrel

[appergb]

User description

What

Splits the 2757-line src-tauri/src/persistence.rs god-file into a focused
persistence/ module — behavior-unchanged, pure move + re-export. Part of #697.

File	Lines	Concern
mod.rs	121	shared fs/io helpers (data_dir, ensure_dir, atomic_write, read_or_default), HISTORY_CAP/PREFERENCES_FILE, module wiring
paths.rs	345	models / recordings / Foundry roots + migration helpers
credentials.rs	880	OS credential vault — CredsRoot model, keyring/android/legacy, CredentialAccount, CredentialsSnapshot, CredentialsVault
style_pack.rs	910	StylePackStore + ZIP import/export + prefs reconciliation
history.rs	135	HistoryStore
dictionary.rs	206	DictionaryStore + vocab presets
preferences.rs	145	read_preferences + PreferencesStore
correction.rs	136	CorrectionRuleStore

How / invariants

• Public surface unchanged. Every previously-pub item is re-exported with pub use <submodule>::*, so crate::persistence::* is identical and zero call sites changed (verified against coordinator, commands, asr/local/models).
• Pure move. No logic, signatures, public API, or UI touched.
• Shared helpers stay private in mod.rs; child modules reach them via super:: (parent items are visible to descendants — no visibility widening needed).
• Glob re-exports are deliberate: they keep cfg-gated items (Android #[cfg(target_os="android")], Windows foundry_*) resolution-safe on every target, avoiding the explicit-pub use breakage that sank the earlier types.rs split. The only import tweak is gating use anyhow::anyhow / use std::fs in credentials.rs so Android sees no new unused-import warning.
• Tests moved next to the code they cover (chunk-payload → credentials, prefs migration → preferences, vocab roundtrip → dictionary, correction syntax → correction, model-root → paths, style-pack sync → style_pack).

credentials.rs (880) and style_pack.rs (910) stay above the ~800 soft guideline on purpose: each store shares private field / cache-state access with its helpers, so splitting them further would force pub(super) cross-module plumbing — the exact fragility this refactor is avoiding. Open to a follow-up sub-split if preferred.

Test plan

• cargo fmt — clean
• cargo check — 0 errors, 0 new warnings in persistence/
• cargo clippy --no-deps — clean (the 3 persistence lints are pre-existing, on verbatim-moved code)
• cargo test --lib — 446 passed, 0 failed (count unchanged)
• CI: Linux / Windows / macOS / Android build jobs (cross-platform cfg code can't be compiled on the macOS dev box)

Base: beta.

---

PR Type

Enhancement

---

Description

• Split 2757-line persistence.rs into domain submodules

• Each submodule owns one store: credentials, style_pack, paths, dictionary, history, correction, preferences

• Re-export via pub use barrel, zero call-site changes

• Shared filesystem helpers stay private in mod.rs

---

Diagram Walkthrough

flowchart LR
  A["persistence.rs (2757 lines)"] --> B["mod.rs (helpers, consts, re-exports)"]
  A --> C["credentials.rs (OS vault)"]
  A --> D["style_pack.rs (pack store + ZIP)"]
  A --> E["paths.rs (storage paths)"]
  A --> F["dictionary.rs (vocab store)"]
  A --> G["history.rs (dictation history)"]
  A --> H["correction.rs (correction rules)"]
  A --> I["preferences.rs (user prefs store)"]
  B --> C
  B --> D
  B --> E
  B --> F
  B --> G
  B --> H
  B --> I

Loading

File Walkthrough

	Relevant files
Enhancement	8 files mod.rs Module wiring, shared helpers, and glob re-exports              +121/-0  credentials.rs OS credential vault store                                                                +880/-0  style_pack.rs Style-pack store with ZIP import/export                                    +910/-0  paths.rs Storage path resolution for models, recordings, Foundry    +345/-0  dictionary.rs Vocabulary dictionary store and vocab presets                        +206/-0  history.rs Dictation history store with retention                                      +135/-0  correction.rs Correction-rule store                                                                        +136/-0  preferences.rs User preferences store with streamingInsert migration        +145/-0
Additional files	1 files persistence.rs +0/-2757

---

[github-actions]

PR Reviewer Guide 🔍

Here are some key observations to aid the review process:

🎫 Ticket compliance analysis 🔶 697 - Partially compliant Compliant requirements: Split persistence.rs into focused submodules: credential, style_pack, paths, dictionary, history, preferences, correction Public surface unchanged (all previously pub items re-exported via pub use submodule::*) No logic, signatures, or UI touched (pure move) Shared helpers remain private in mod.rs; child modules use super:: Non-compliant requirements: None from code inspection Requires further human verification: Actual CI runs (cargo test, tsc, build, all-platform) are needed to confirm cross-platform compatibility (e.g., Windows cfg-gated types)

⏱️ Estimated effort to review: 2 🔵🔵⚪⚪⚪

🧪 PR contains tests

🔒 No security concerns identified

⚡ No major issues detected