docs: archive v1.3 and v2.0 milestones with roadmap, requirements, and retrospective

.planning/debug/client-w0-undefined-after-login.md

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+---
+status: awaiting_human_verify
+trigger: "Client-side error 'can't access property id, w[0] is undefined' occurs after login"
+created: 2026-04-08T00:00:00Z
+updated: 2026-04-08T00:00:00Z
+---
+
+## Current Focus
+
+hypothesis: CONFIRMED — AddToThreadModal.tsx has an unguarded activeThreads[0].id in a useEffect dependency array, which throws when there are no active threads (new user after login)
+test: Root cause confirmed by code reading
+expecting: Fix by replacing activeThreads[0].id with activeThreads[0]?.id in the dependency array
+next_action: Apply fix
+
+## Symptoms
+
+expected: After login, app loads normally and shows user's collection
+actual: Error thrown client-side: "can't access property 'id', w[0] is undefined"
+errors: "can't access property 'id', w[0] is undefined" — minified variable name, from production/built bundle
+reproduction: Happens after logging in (OIDC via Logto)
+started: Unclear when it started, user noticed it now
+
+## Eliminated
+
+- hypothesis: Bug is in auth hooks or route guards
+  evidence: useAuth.ts and __root.tsx are clean — auth handles null/undefined safely
+  timestamp: 2026-04-08T00:00:00Z
+
+- hypothesis: Bug is in categories[0].id access in CreateThreadModal, ManualEntryForm, or AddToCollectionModal
+  evidence: All three guard with `categories && categories.length > 0` before accessing [0].id
+  timestamp: 2026-04-08T00:00:00Z
+
+## Evidence
+
+- timestamp: 2026-04-08T00:00:00Z
+  checked: AddToThreadModal.tsx lines 62-68
+  found: useEffect dependency array evaluates `activeThreads[0].id` unconditionally. When activeThreads is empty (new user after login with no threads), this throws TypeError.
+  implication: This is the root cause. The guard `activeThreads.length === 0` inside the effect body does NOT protect the dependency array itself — React evaluates the dep array on every render.
+
+## Resolution
+
+root_cause: In AddToThreadModal.tsx, the useEffect dependency array at lines 62-68 directly accesses `activeThreads[0].id` without optional chaining. When a user logs in with no active threads (empty array), React evaluates this expression during render and throws "can't access property 'id', w[0] is undefined".
+fix: Replace `activeThreads[0].id` with `activeThreads[0]?.id` in the useEffect dependency array
+verification: Fix applied — changed `activeThreads[0].id` to `activeThreads[0]?.id` in useEffect dependency array. This prevents the TypeError when activeThreads is empty.
+files_changed: [src/client/components/AddToThreadModal.tsx]