Delete a run/session completely (#23)

[ableinc]

Closes #23

What the agent did

Summary

Implemented issue #23 following the approved plan:

Backend

• internal/store/store.go: added DeleteRun(ctx, runID) — deletes events, sessions, and the runs row in one transaction, returning ErrNotFound if the run didn't exist.
• internal/server/server.go: added deleteRun handler and registered POST /runs/:id/delete. It fetches the run, cancels it first via the controller if not yet terminal (fire-and-forget, since cancellation is async), deletes the DB rows, then best-effort removes the transcript file (os.Remove, ignoring not-exist).
• Tests: TestDeleteRun/TestDeleteRunNotFound in internal/store/store_test.go; TestDeleteRun/TestDeleteRunStopsInFlightRunFirst in internal/server/server_test.go (using the existing fakeController to assert Cancel is/isn't called appropriately).

Frontend (internal/web/assets/app.js, app.css)

• Added runActionButtons(run, onDeleted) shared by the runs list and run detail page: a "Stop" button (shown only for in-flight statuses) and a "Delete" button gated by window.confirm(...), which stops-then-deletes via the API.
• Runs list table gained an "Actions" column; run detail page gained an action row under the title, navigating back to #/runs after a successful delete.
• Added a minor .row-actions flex-wrapper CSS rule.

Verification

• go build ./... succeeds.
• go test ./internal/store/... ./internal/server/... passes, including the new tests.
• go test ./... shows only pre-existing, unrelated failures in internal/git (git-identity assertions failing due to this sandbox's environment, not touched by this change).
• Note: this repo requires a local, gitignored config.json/toolchain workaround to run go test in this sandbox (read-only Go sumdb cache blocked the pinned go1.26.5 toolchain fetch) — worked around locally with GOPATH=/tmp/gopath GOTOOLCHAIN=auto and a temporary config.json copied from config.example.json, both cleaned up before committing; nothing environment-specific was committed.

Reviewer should double check the route verb choice (POST /runs/:id/delete, matching existing POST /runs/:id/cancel convention) and the native window.confirm() choice for the confirmation dialog — both were flagged as judgment calls in the plan and I followed the plan's recommendation for each.

Verification

Tests failed (make test). This PR is a draft — the failure is reported rather than hidden, so you can judge whether the change is salvageable.

Test output (tail)

go test -race ./...
go: golang.org/toolchain@v0.0.1-go1.26.5.linux-arm64: verifying module: golang.org/toolchain@v0.0.1-go1.26.5.linux-arm64: open /home/node1/go/pkg/sumdb/sum.golang.org/latest: read-only file system
make: *** [Makefile:131: test] Error 1

Changes

internal/server/server.go      | 32 +++++++++++++++++++++++
 internal/server/server_test.go | 58 ++++++++++++++++++++++++++++++++++++++++++
 internal/store/store.go        | 35 +++++++++++++++++++++++++
 internal/store/store_test.go   | 43 +++++++++++++++++++++++++++++++
 internal/web/assets/app.css    |  5 ++++
 internal/web/assets/app.js     | 52 ++++++++++++++++++++++++++++++++++++-
 6 files changed, 224 insertions(+), 1 deletion(-)

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Opened automatically by coding-agent-loop (run f858df05-637d-4f9b-8dbf-c9200f2c67aa, attempt 2, model claude-sonnet-5, cost $0.8746, session 58eccd94-bd40-4302-b92c-5d89f902ea28). Nothing here has been reviewed by a human yet.