dropthejase gives the review grid its own chat assistant

- agents/app/tabular/: new Strands agent mirroring main structure; single
  read_table_cells tool; system prompt built per-request from review context
- backend: replace POST /:reviewId/chat (runLLMStream) with two thin endpoints:
  POST /:reviewId/chats (create) and POST /:reviewId/chats/:chatId/messages (persist)
- frontend: streamTabularChat now calls AgentCore louisTabular URL; TRChatPanel
  pre-creates chat record before streaming, persists turn after [DONE]
- config: NEXT_PUBLIC_AGENTCORE_TABULAR_URL added to config + env example
- docs: README and ARCHITECTURE updated

Single Lambda reads S3 once, applies all resolutions in memory, writes once.
Frontend handleAll sends one batch request per document instead of N parallel.
Also constrains agent to single-paragraph edits to avoid cross-para deletion failures.

- Parse columns_config from RDS Data API string before use in generate endpoint
- Remove stale 'const client = client' self-references in bedrock.ts (ReferenceError)
- Rename queryGeminiAllColumns/queryGemini to queryBedrockAllColumns/queryBedrock
- Add ::uuid cast to :pid${i} params in shared-by-project query

Aurora Data API returns jsonb columns as raw strings. withWorkflowAccess
was spreading the raw DB row without parsing columns_config, causing
TypeError: .sort is not a function on the WorkflowPage and corrupt
double-serialized data when creating a tabular review from a custom workflow.

Parse in withWorkflowAccess so all workflow endpoints (GET /, GET /:id,
PUT, PATCH) are covered by a single fix.

Tabular review chat messages now stored in S3 (conversations/{chatId}/messages.json)
using the same Strands snapshot format as the main chat agent. This gives the tabular
agent full conversation history on every turn (agent memory).

- agent.ts: loadMessages (S3 GET) + AfterInvocationEvent hook (S3 PUT)
- index.ts: load previous messages, pass to createAgent, tail-buffer suppresses <CITATIONS>
- sessions.ts: new shared lib - S3 read/write + snapshotMessagesToSessionMessages
- chat.ts: remove ~250 lines of private session logic, import from sessions.ts
- tabular.ts: replace Aurora message reads/writes with S3 via sessions.ts
- mikeApi.ts + TRChatPanel.tsx: remove Aurora-specific message mapping