refactor(fiction-assistance)!: drop line-editor agent, add proofread and check-consistency commands

Two shifts in scope:

- Remove the line-editor agent. The plugin no longer mutates the
  manuscript — all commands report findings to the conversation
  and leave revisions to the writer.

- Consolidate the consistency surface. /check-voice and
  /check-continuity were narrow checks with overlapping concerns;
  they are replaced by /check-consistency, a single broader pass
  covering author voice, character voice, words-vs-actions
  alignment, and in-world believability. Plot-logic and
  sequencing concerns formerly in /check-continuity are now
  served by /generate-timeline's consistency-issues section.

- Add /proofread for the mechanical layer that previously had no
  command equivalent — grammar, tense, punctuation, spelling,
  agreement, sentence-level clarity. Reports issues; does not edit.

Command count unchanged at nine. The plugin is now agent-free and
mutation-free; every command is read-only on the manuscript.

BREAKING CHANGE: /check-voice and /check-continuity are removed
(superseded by /check-consistency). The line-editor agent is
removed (use /proofread for reporting; the writer makes the edits).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

fiction-assistance/commands/proofread.md

@@ -0,0 +1,59 @@
+---
+description: Proofread and line-edit pass — grammar, tense, punctuation, spelling, mechanical errors. Reports issues; does not edit.
+argument-hint: "[path, glob, or selection]"
+allowed-tools: [Read, Glob, Grep]
+---
+
+Read the text at `$ARGUMENTS` and identify mechanical and sentence-level problems. Report what you find — **do not edit the file**. The writer is making the changes themselves.
+
+## What to check
+
+### Grammar and mechanics
+- **Verb tense** — consistency within a sentence, paragraph, and across the piece; unintended slips between past and present
+- **Subject-verb agreement** — number, person, indefinite pronouns
+- **Pronoun-antecedent agreement** — number, gender, unclear reference
+- **Modifiers** — dangling, misplaced, squinting
+- **Parallelism** — in lists, comparisons, correlative conjunctions
+
+### Punctuation and conventions
+- **Commas** — splices (unless deliberate), missing commas after introductory phrases, serial comma consistency
+- **Semicolons, colons, dashes** — used correctly and consistently
+- **Quotation marks and dialogue tags** — punctuation inside/outside, comma vs. period before tags, paragraph breaks per speaker
+- **Apostrophes** — possessive vs. plural, *its* vs. *it's*
+- **Hyphenation** — compound modifiers, hanging hyphens, en/em dash usage
+- **Capitalization** — proper nouns, titles, after colons, in dialogue
+
+### Spelling and word choice
+- **Misspellings** — including names that drift across the manuscript
+- **Homophones** — their/there/they're, your/you're, peek/peak/pique, etc.
+- **Confused words** — affect/effect, fewer/less, who/whom, lie/lay, etc.
+- **Repeated words** — accidental doubles, awkward proximity repetition
+
+### Sentence-level clarity
+- **Sentence fragments** — unintentional vs. stylistic; flag the unintentional ones
+- **Run-ons and comma splices** — flag unless clearly deliberate for voice
+- **Awkward constructions** — passive where active would be clearer, nominalization piles, tangled syntax
+- **Word order** — modifier placement, sentence rhythm
+- **Tightening opportunities** — redundancies, throat-clearing phrases, weak intensifiers (very, really, quite, just), filter words (saw, heard, felt, noticed) when they distance the reader
+
+### Style consistency
+- **Spelling/style variants** — US vs. UK, *grey/gray*, *-ize/-ise*, etc. Pick one and flag drift
+- **Number formatting** — when to spell out, when to use digits
+- **Time, date, and unit formatting**
+- **Italics, bold, small caps** — consistency for thoughts, emphasis, foreign words, titles
+
+## Output format
+
+For each issue:
+
+- **Location** — chapter/scene/line if known, with a short quoted excerpt
+- **Issue type** — one of the categories above
+- **What's wrong** — concrete diagnosis
+- **Suggested fix** — show the corrected version, not just the rule
+
+Group issues by type so the writer can attack one category at a time. Close with:
+
+- **Summary** — total issues by category
+- **Patterns** — recurring problems the writer should watch for in future drafts (e.g., "consistent tense-slip in interior-thought passages")
+
+Be a careful reader, not a pedant. Don't flag stylistic choices that read as deliberate — fragments for voice, comma splices for rhythm, dialogue that breaks rules to sound right. Note them only if a choice looks accidental.