feat(REQ-001): add portfolio comment history API, CLI, repository, migration, and tests

Agent-Logs-Url: https://github.com/genichin/portfolio-hub/sessions/64fc2cec-78f5-41d1-99a4-45f868781edd

Co-authored-by: genichin <4282227+genichin@users.noreply.github.com>

docs/portfoliohub-spec.md

@@ -217,6 +217,36 @@ Base routes:
   - `keep_ledger` (bool, default `false`)
 - Response `204`: no content
 
+#### Create Comment
+
+- `POST /portfolios/{portfolio_id}/comments`
+- Auth: `trade-write`
+- Body: `CommentCreateRequest` (`content: str`)
+- Response `201`: `CommentResponse`
+- Response `404`: portfolio not found
+
+#### List Comments
+
+- `GET /portfolios/{portfolio_id}/comments`
+- Auth: `read`
+- Response `200`: array of `CommentResponse`, sorted by `created_at DESC`
+- Response `404`: portfolio not found
+
+#### Update Comment
+
+- `PATCH /portfolios/{portfolio_id}/comments/{comment_id}`
+- Auth: `trade-write`
+- Body: `CommentUpdateRequest` (`content: str`)
+- Response `200`: `CommentResponse`
+- Response `404`: portfolio or comment not found
+
+#### Delete Comment
+
+- `DELETE /portfolios/{portfolio_id}/comments/{comment_id}`
+- Auth: `trade-write`
+- Response `204`: no content
+- Response `404`: portfolio or comment not found
+
 ### 7.3 Strategy Set Endpoints
 
 #### List Strategy Sets
@@ -473,6 +503,14 @@ Bootstrap rule:
 
 - `infer_symbol: str | null`
 
+`CommentCreateRequest`
+
+- `content: str`
+
+`CommentUpdateRequest`
+
+- `content: str`
+
 `CreateStrategySetRequest`
 
 - `name: str`
@@ -529,6 +567,14 @@ Bootstrap rule:
 
 - `detail: str`
 
+`CommentResponse`
+
+- `id: str`
+- `portfolio_id: str`
+- `content: str`
+- `created_at: datetime | null`
+- `updated_at: datetime | null`
+
 `BotPrincipalResponse`
 
 - `id: str`
@@ -565,6 +611,13 @@ Portfolio subcommands:
 - `portfoliohub portfolio reset <portfolio_id> [--infer-symbol ...] [--force]`
 - `portfoliohub portfolio delete <portfolio_id> [--keep-ledger] [--force]`
 
+Portfolio comment subcommands:
+
+- `portfoliohub portfolio comment add <portfolio_id> --content <text>`
+- `portfoliohub portfolio comment list <portfolio_id>`
+- `portfoliohub portfolio comment update <portfolio_id> <comment_id> --content <text> [--force]`
+- `portfoliohub portfolio comment delete <portfolio_id> <comment_id> [--force]`
+
 Strategy subcommands:
 
 - `portfoliohub strategy list`