Support Copilot CLI multi-storage recall and provider-based fallback

[jshessen]

Summary

This PR resolves Copilot CLI 1.0.34+ storage compatibility by introducing provider-based multi-storage recall instead of assuming a single SQLite layout.

Closes #3

Storage model coverage by provider

Provider	Storage location(s)	Storage format	Commands supported
cli (Copilot CLI)	~/.copilot/session-store.db	SQLite (legacy/current where present)	list, search, show, files, checkpoints, health, schema-check
cli fallback	~/.copilot/session-state/*/events.jsonl	JSONL events	list, search, show (schema-check reports compatibility mode)
vscode	~/.config/Code/User/workspaceStorage/**/chatSessions/*.jsonl (+ flatpak/snap variants)	JSONL logs	list, search, show, files
jetbrains	~/.config/github-copilot/chat-sessions/* + related chat files	file-backed JSON/session logs	list, search, show, files
neovim	~/.config/github-copilot/** and ~/.local/share/nvim/** chat JSON/JSONL	file-backed JSON/JSONL	list, search, show, files

Environment overrides supported

• SESSION_RECALL_DB
• SESSION_RECALL_CLI_STATE_ROOT
• SESSION_RECALL_VSCODE_STORAGE
• SESSION_RECALL_JETBRAINS_ROOT
• SESSION_RECALL_NEOVIM_ROOT

Runtime behavior and fallback semantics

Provider discovery

At runtime, providers are discovered and filtered to those actually available on the machine:

• CLI provider is available if either SQLite DB exists or session-state event files exist.
• File-backed providers are available when their roots exist.

Command behavior in multi-storage mode

• list, search, show, files, checkpoints now route through active providers.
• schema-check is provider-aware:
  • Performs strict schema checks when CLI SQLite is present.
  • Returns compatibility detail (session-state-or-sqlite) when fallback event storage is active.
• health is provider-aware:
  • Runs SQLite health dimensions when SQLite is available.
  • Falls back to provider compatibility dimensions when SQLite is not available.

UX and recall quality improvements

• Added session-recall repos to summarize discovered repositories/workspaces across providers.
• Improved repository attribution for CLI session-state parsing.
• Improved list/repos alignment and sparse-scope behavior so recall output better matches discovered session reality.

What changed

• Added provider architecture:
  • src/session_recall/providers/ (base.py, discovery.py, copilot_cli.py, file_backends.py, common.py)
• Added repo discovery command:
  • src/session_recall/commands/repos.py
• Updated command paths for provider fallback and multi-storage context:
  • list, search, show, files, checkpoints, health, schema-check
• Improved repo detection/output formatting:
  • src/session_recall/util/detect_repo.py
  • src/session_recall/util/format_output.py
• Added/updated tests:
  • test_provider_backends.py
  • test_health_schema_multistorage.py
  • test_repo_scope_fallback.py
  • test_repos_command.py
  • updates in test_list_sessions.py

How this differs from PR #4

PR #4 primarily introduces a DB-layer adapter approach (db/jsonl_store.py + connect/schema integration).

This PR addresses the same issue via provider routing and command-layer fallback, including:

• dynamic provider discovery,
• explicit session-state support for CLI,
• cross-surface file-backed providers (VS Code / JetBrains / Neovim),
• and provider-aware health/schema semantics.

Both aim at Issue #3 but with different architecture and operational surface area.

Validation

• pytest src/session_recall/tests/ -q → 105 passed
• ruff check src/ → all checks passed
• Focused suite:
  • pytest -q src/session_recall/tests/test_provider_backends.py src/session_recall/tests/test_repo_scope_fallback.py src/session_recall/tests/test_repos_command.py src/session_recall/tests/test_list_sessions.py src/session_recall/tests/test_health_schema_multistorage.py → 18 passed

CONTRIBUTING checklist

• Tests pass: pytest src/session_recall/tests/ -q
• Lint passes: ruff check src/
• No new runtime dependencies added
• Docs updated for behavior changes (README.md)