feat: derive dashboard panels and actions from solver capabilities

[florian-simvia]

What

Dashboard panels and action buttons are now derived from what the solver adapter
actually implements, instead of a hand maintained dashboard_panels declaration
whose default was "show everything".

A capability exists when the thing that feeds it is no longer the base default:
an overridden method (find_residuals_files, list_probe_files,
build_restart_args, gui_argv) or a non-empty declaration (compare_kinds,
performance_columns, control_actions). dashboard_panels follows from that
set, /api/app_config serves it, and FastAPIContext.require_capability
enforces it server side.

	code_saturne	stub	code_aster
Panels	7 (unchanged)	status, compare, tail, errors	status, compare, tail, errors
Capabilities	all 7	compare, control	compare

Why

CodeAsterAdapter never trimmed dashboard_panels, so the dashboard offered a
Residuals chart for a solver that produces no residuals, plus a Probes panel, a
Timing panel and an empty Compare selector.

The action buttons were worse: canControl and canRestart depended only on
case status, never on the solver, and /api/app_config did not expose
control_actions. On a running code_aster case, Stop, Extend, Checkpoint, Flush,
Restart and Open GUI were all enabled and all failed on click, Restart with an
HTTP 500 (a client error reported as a server fault).

Deriving instead of declaring makes the inconsistency impossible by
construction, and adapters can no longer shadow the derivation: declaring
dashboard_panels or capabilities raises TypeError at import time.

How to test

pytest -q                                   # 371 passed, 3 skipped
cd frontend && pnpm check && pnpm build

Note: the web tests need the optional extra (pip install -e ".[web,dev]"),
otherwise 54 of them are skipped.

Then, against a code_aster campaign (examples/codeaster-cube):

csauto prepare doe.csv TEMPLATE RUNS
csauto doctor RUNS        # reports the derived panels and capabilities
csauto serve RUNS

Expected: four panels only (Status, Compare, Log Tail, Recent Errors), no Stop,
no More menu, no Restart, no Open GUI column, and a Compare panel that offers
doe_row.csv. With solver = "code_saturne", nothing changes.

Direct API calls are refused with a 400 naming the solver:

curl -X POST localhost:8000/api/control_case -H 'Content-Type: application/json' \
  -d '{"cases":["case0001"],"action":"stop"}'
# {"detail":"Solver 'code_aster' does not support control"}

Checklist

• Tests pass locally (pytest -q)
• Frontend builds (cd frontend && pnpm build)
• No linting errors (ruff check . && ruff format --check .)
• frontend/dist/ is up-to-date (committed after pnpm build)