fix(agent-config): make effect dependencies explicit

[beruro]

Problem

Agent configuration hooks suppressed React dependency lint in four places. The shared loader accepted a caller-managed dependency array, SDE load/save callbacks hid workspacePath behind a ref, and OS credential checks reacted only to loaded while reading config. This obscured the actual scope lifecycle and allowed a slow credential response for an old model to overwrite the current model's status.

Solution

Make callback identity the configuration-scope contract: useAgentConfigBase reloads when its stable load callback changes, and OS/SDE callers declare their real dependencies. Derive OS credential synchronization from the current model and guard async results with a monotonically increasing generation so stale or unmounted requests cannot write state. Remove all four dependency suppressions in this group and add focused lifecycle tests for reload, save, and stale-response behavior.

Potential risks

The load contract now requires callers to memoize load; both production callers do so and are covered. UI behavior was not manually exercised in a live Tauri/WebView session, so backend-command integration remains an unverified path. Rollback is a normal commit revert; there are no schema, persistence-format, dependency, or public IPC changes.

Verification

• ./node_modules/.bin/vitest run src/modules/MainApp/AgentOrgs/config/osAgent/useAgentConfigBase.test.ts src/modules/MainApp/AgentOrgs/config/osAgent/useOSAgentConfig.credentials.test.ts src/modules/MainApp/AgentOrgs/config/sdeAgent/useSdeAgentConfig.dependencies.test.ts — 3 files and 4 tests passed.
• ./node_modules/.bin/eslint on all six changed files — passed.
• ./node_modules/.bin/prettier --check on all six changed files — passed.
• npm run typecheck — passed.
• Repository pre-commit hook (lint-staged, scoped TypeScript check, commit stats) — passed.
• git diff --check origin/develop...HEAD — passed.

Effects

• The config-load Effect synchronizes with Tauri config reads and ignores stale or unmounted resolutions.
• Save and credential timers retain symmetric unmount cleanup.
• The credential-check Effect synchronizes the current model with the external key check; a generation guard rejects stale responses.

No rendered markup or styling changed, so screenshots are not useful for this PR.