fix(plugin): the session-start Goal line cuts at a word and says where the rest is (#4036)

A raw 200-char slice ended mid-word with nothing marking the cut, so a
reader took half a sentence for the whole goal. _goal_line flattens the
goal to one line, trims at a word break with an ellipsis, and points at
enter_project(id) when it cut.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/scribe/services/plugin_context.py

@@ -16,6 +16,7 @@ from __future__ import annotations
 
 import logging
 import re
+import textwrap
 import time
 
 
@@ -41,6 +42,10 @@ _MAX_CHARS = 9000
 # Max chars of a Process body to fold into the auto-surface description.
 _PROC_PREVIEW_CHARS = 200
 
+# Max chars of the project goal on the session-start Goal line. The full goal is
+# one enter_project away; a cut says so rather than ending mid-word (#4036).
+_GOAL_CHARS = 200
+
 # --- Knowledge auto-inject (Path A: per-turn awareness push) -----------------
 # Per-user settings (keys live in the generic settings table). The threshold is
 # deliberately STRICTER than the pull-search default (embeddings
@@ -2140,6 +2145,23 @@ def _stamp_line(path: str, stamped: list[dict]) -> str:
 
 
 
+def _goal_line(goal: str, project_id: int) -> str:
+    """The Goal line, trimmed at a word break with a visible cut.
+
+    A raw slice ended mid-word with nothing to say more existed, so a reader
+    took half a sentence for the whole goal (#4036).
+    """
+    if not goal:
+        return ""
+    flat = " ".join(goal.split())
+    if len(flat) <= _GOAL_CHARS:
+        return f"Goal: {flat}"
+    short = textwrap.shorten(flat, width=_GOAL_CHARS, placeholder="…")
+    if short == "…":  # one unbroken word longer than the cap
+        short = flat[: _GOAL_CHARS - 1] + "…"
+    return f"Goal: {short} (full goal: `enter_project({project_id})`)"
+
+
 async def build_session_context(
     user_id: int, project_id: int = 0, unbound_repo: str = ""
 ) -> dict:
@@ -2185,7 +2207,7 @@ async def build_session_context(
             lines += [
                 "",
                 f"## Active project: {project.title} (id {project.id})",
-                f"Goal: {goal[:200]}" if goal else "",
+                _goal_line(goal, project.id),
                 f"Open todo tasks: {open_count}",
             ]