fix(server): annotate SQLAlchemy result rows for 2.1 type inference [SAO-17580]

[josjeon]

Summary

make typecheck currently fails on main and on every open PR. This annotates the four call sites that SQLAlchemy 2.1.0 broke, unblocking merges.

The failure belongs to no branch's changes.

What happened

SQLAlchemy 2.1.0 no longer lets mypy infer the element type through result.scalars().all():

server/src/agent_control_server/services/control_bindings.py:282:
  error: Need type annotation for "rows" (hint: "rows: list[<type>] = ...")  [var-annotated]
Found 1 error in 1 file (checked 51 source files)
make: *** [Makefile:138: typecheck] Error 1

The repository lock pins 2.0.51, which still infers it, so the error appears only in CI, where dependencies resolve fresh. Main's own run at bd7d91f installs both and reports the error in the same log:

+ mypy==2.3.1
+ sqlalchemy==2.1.0
server/src/agent_control_server/services/control_bindings.py:282: error: Need type annotation for "rows"

Evidence this is not branch-specific

Branch	Date	CI
main	2026-09-22	success
main	2026-09-24	failure
fix/sao-17418-runtime-token-auth	2026-09-24	success
fix/sao-17418-runtime-token-auth	2026-09-28	failure

SQLAlchemy 2.1.0 was released between those dates, and the flagged file is not in the diff of either affected PR. Re-running the job does not clear it: CI resolves 2.1.0 again each time, so the failure is deterministic rather than flaky.

What changed

Four sites share the pattern. CI reports only the first, so fixing them one at a time would surface the next on the following run.

File	Annotation
services/control_bindings.py:282	rows: list[ControlBinding]
services/controls.py:306	versions: list[ControlVersion]
services/controls.py:512	controls: list[Control]
endpoints/agents.py:463	agents: Sequence[Agent]

agents.py keeps Sequence rather than list because that call site does not wrap the result in list() and only reads and slices it. Sequence and Agent were already imported there.

Scope

• Type annotations only. No runtime behavior changes, no control flow, no queries touched.
• Deliberately out of scope: raising the SQLAlchemy floor in pyproject.toml or regenerating the lock. That is a wider dependency decision, and these annotations are correct under either version.

Risk and Rollout

• Risk level: minimal. Annotations are erased at runtime.
• No migration or configuration change.
• Rollback plan: revert this PR.

Testing

• mypy server/src clean under the locked versions: 51 source files, no issues.
• ruff check server/src clean.
• Full server test suite: not run locally. The local Docker daemon is unresponsive, so the Postgres-backed suite cannot start. CI covers it here, and the change is annotations only.
• Reproduced the failure locally against CI's resolved versions: not possible right now, the internal package index returns 401. The CI log for main is cited above instead.

Checklist

• Linked issue: SAO-17580.
• Documentation/examples: no update required.
• Unblocks fix(server): Reject malformed runtime-token target context before authorization [SAO-17522] #268 (approved, blocked only by this) and feat(server): Add validation details to upstream auth logs [SAO-17523] #270. Both touch different files, so this merges independently of either.

AI Tool Assistance Usage Statement

• AI assistance was used to draft parts of the implementation, that was subsequently modified and extended.
• AI assistance was used in generating tests/documentation/comments for this change.
• AI assistance was used for optimizing/troubleshooting/refactoring existing code in this change.
• AI assistance was used to draft this entire change as is.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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