feat(agent): added per-call tool concurrency resolver and parallel bash execution

- Extended `AgentTool.concurrency` to accept per-call resolver functions and resolved concurrency mode from each tool call, falling back to exclusive on resolver errors.
- Updated BashTool to schedule non-PTY calls as shared and PTY calls as exclusive so non-interactive bash calls can run in parallel within one message.
- Tracked in-use persistent shell sessions in the bash executor and routed overlapping calls on the same session key to isolated one-shot shells while preserving owner session availability.

docs/tools/bash.md

@@ -144,7 +144,7 @@ Stdout and stderr are merged before the model sees them. Definite non-zero exit
 - Artifact allocation / artifact save failures are swallowed in `saveBashOriginalArtifact()` and `OutputSink.#createFileSink()`; execution continues without that artifact.
 
 ## Notes
-- `strict = true` and `concurrency = "exclusive"` are set on `BashTool`; the tool does not run concurrently with another bash tool call in the same session.
+- `strict = true` is set on `BashTool`; `concurrency` is resolved per call: `pty: true` is `"exclusive"` (it takes over the terminal UI), everything else is `"shared"`, so multiple non-pty bash calls in one assistant message run in parallel. When parallel calls overlap on the same shell session key, the first owns the persistent `Shell`; the rest run in isolated one-shot shells (see `shellSessionsInUse` in `bash-executor.ts`).
 - `command` URL expansions shell-escape replacements; `env` and `cwd` expansion use `noEscape: true` because they become environment values / filesystem paths, not shell text.
 - `checkBashInterception()` blocks only when the matching rule's `tool` name is present in `ctx.toolNames`; missing tools disable their corresponding rule.
 - Default interceptor rules come from `DEFAULT_BASH_INTERCEPTOR_RULES` in `packages/coding-agent/src/config/settings-schema.ts`: