feat(sources v1): the agent locates files itself — ls/find/grep + tool-call cards

User pivot (2026-09-19): no attachments UI at all. Pasting paths is native
for technical users and alien for everyone else - so the agent gets the
tools to find what the learner merely NAMES. The learner communicates in
messages; the agent locates and reads. Zero cross-stream seams: paths
already live in tool parts, so the sources "list" is the transcript.

- ls/find/grep: pi-verbatim schemas, descriptions, and output formats
  (fd's glob semantics, rg's path:line: match format, pi's truncation
  notices), ported to pure Node - no binaries, no shell-out, read-only by
  construction. Deltas from pi: home-anchored resolution (the harness has
  no cwd), .gitignore replaced by hard noise exclusions
  (node_modules/.git/Library/.Trash), 10s walk timeout with partial results.
- read: description swapped to pi-verbatim (doctrine moved to the prompt);
  relative paths now resolve against the learner's home like the rest.
- prompts/shared/05-learner-files.md: one minimal doctrine fragment
  composed into BOTH agents (composeInstructions grew a shared/ dir,
  before the agent's own fragments). teacher/30-jobs.md keeps only the
  pdf-dispatch addendum.
- ToolCallCard: the generic quiet tool-call card the user specced -
  collapsed one-liner (tool name + headline argument), expandable to full
  input/output, errors red, image payloads never render. Registered for
  read/ls/find/grep.
- ui-message.ts: TeacherUITools entries for the four tools (mechanical).
- tests: fs-tools suite (glob semantics, pi formats, exclusions, limits),
  registry/card renders, shared-fragment composition pins, tool-registry
  key updates, read re-anchor.

src/agent/tools.ts

@@ -12,6 +12,9 @@ import { jobTools, type DemoInput, type ResearchInput, type VisualInput } from "
 import { planTools, type PlanToolContext } from "./tools/plan.ts";
 import { probeDoneTool, type ProbeDoneContext } from "./tools/probe.ts";
 import { readTool } from "./tools/read.ts";
+import { lsTool } from "./tools/ls.ts";
+import { findTool } from "./tools/find.ts";
+import { grepTool } from "./tools/grep.ts";
 
 export { jobTools };
 export type { ProbeDoneContext } from "./tools/probe.ts";
@@ -81,9 +84,13 @@ export function createProberTools(
 			{
 				quiz: probeQuizTool,
 				ask_user_question: askUserQuestionTool,
-				// read is always-on (user-decided 2026-09): the prober inspects
-				// learner-provided source files while assessing the edge.
+				// The learner-filesystem set is always-on (user-decided 2026-09,
+				// sources v1): the prober inspects and LOCATES learner-referenced
+				// files while assessing the edge. Read-only by construction.
 				read: readTool,
+				ls: lsTool,
+				find: findTool,
+				grep: grepTool,
 				...done,
 			},
 			enabled,
@@ -168,9 +175,14 @@ export function createTeacherTools(
 		{
 			quiz: teachQuizToolFor(ctx),
 			ask_user_question: askUserQuestionTool,
-			// read is always-on (user-decided 2026-09): the teacher reads
-			// learner-provided sources on its own terms — nothing auto-injects.
+			// The learner-filesystem set is always-on (user-decided 2026-09,
+			// sources v1): the teacher locates and reads learner-referenced
+			// files on its own terms — nothing auto-injects. Read-only by
+			// construction (fs-shared.ts).
 			read: readTool,
+			ls: lsTool,
+			find: findTool,
+			grep: grepTool,
 			...planTools(ctx),
 			...jobTools({ chatId: ctx.chatId, jobStore: ctx.jobStore, spawn: ctx.spawn }),
 		},