chore(release-plz): give term-styles its own tag namespace

[avihut]

Summary

• Adds a per-package release-plz.toml entry for term-styles mirroring how xtask is configured: own tag template ({{ package }}-v{{ version }}), release = false, publish = false, no changelog.
• Unblocks the Release-plz workflow on master, which has failed on every push since refactor(test-runner): introduce CommandExecutor port at runner/daft seam #521 introduced the term-styles workspace crate.

Why this fixes it

Without a per-package git_tag_name, release-plz uses the workspace-wide v{{ version }} template — the daft tag format — for every crate it discovers. It then picks up the latest v1.13.0 daft tag and attributes it to term-styles:

INFO Latest release of package term-styles: tag `v1.13.0` (version 1.13.0)
ERROR failed to update packages
    0: failed to determine next versions
    1: get cargo package term-styles from worktree at "/tmp/release-plz-term-styles-…/worktree"
    2: Failed to find package "term-styles"

release-plz then tries to read term-styles/Cargo.toml from a worktree checked out at v1.13.0, where the crate doesn't exist yet (it was added after v1.13.0 was cut), and the run aborts.

With a distinct tag template, release-plz looks for term-styles-v* tags, finds none, treats the crate as never released, and skips it — same defense xtask already uses.

Fixes #527

Test plan

• Release-plz workflow run on this PR's branch parses the manifest without erroring out on term-styles.
• After merge, the next push to master triggers a Release-plz run that completes successfully and either opens a release PR for daft or no-ops.

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