feat: mount user repo as read-only with writable shannon overlay (#273)

* feat: mount user repo as read-only with deliverables bind-mount overlay

* feat: add playground and .playwright-cli overlay mounts

* feat: add filesystem context to pipeline-testing prompts

* fix: use explicit REPO_PATH in filesystem prompt for clarity

* fix: update filesystem prompts with playground notes and absolute screenshot paths

* feat: namespace writable overlays under .shannon/ to avoid polluting host repo

* refactor: rename playground to scratchpad

* fix: redirect playwright-cli output to writable .shannon/ overlay

* fix: pre-create .shannon/ overlay mount points for Linux compatibility

* fix: exclude nested node_modules and dist from Docker build context

* fix: enforce LF line endings for shell scripts on Windows

apps/worker/prompts/exploit-injection.txt

@@ -70,13 +70,13 @@ Remember: An unproven vulnerability is worse than no finding at all - it wastes
 </login_instructions>
 
 <starting_context>
-- Your **actionable exploitation queue** is located at `deliverables/injection_exploitation_queue.json`. This is your to-do list, containing the precise targets identified by the analysis phase. You MUST process every vulnerability in this queue.
+- Your **actionable exploitation queue** is located at `.shannon/deliverables/injection_exploitation_queue.json`. This is your to-do list, containing the precise targets identified by the analysis phase. You MUST process every vulnerability in this queue.
 
 **INTELLIGENCE GATHERING PHASE (MANDATORY):**
 Before beginning exploitation, read these strategic intelligence files in order:
-1. `deliverables/pre_recon_deliverable.md` - Architecture overview, exact vulnerable code snippets, database details, authentication mechanisms
-2. `deliverables/recon_deliverable.md` - Complete API inventory, input vectors, code pointers with file:line references  
-3. `deliverables/injection_analysis_deliverable.md` - Strategic context from analysis specialist, WAF behavior, database technologies
+1. `.shannon/deliverables/pre_recon_deliverable.md` - Architecture overview, exact vulnerable code snippets, database details, authentication mechanisms
+2. `.shannon/deliverables/recon_deliverable.md` - Complete API inventory, input vectors, code pointers with file:line references
+3. `.shannon/deliverables/injection_analysis_deliverable.md` - Strategic context from analysis specialist, WAF behavior, database technologies
 
 **INTELLIGENCE-INFORMED EXPLOITATION:**
 - Use exact query or command structures provided in intelligence reports to construct precise payloads.
@@ -91,13 +91,13 @@ Before beginning exploitation, read these strategic intelligence files in order:
 
 **Phase Sequence:** VULN ANALYSIS (Complete) → **INJECTION EXPLOITATION (You)** → FINAL REPORT (next phase)
 
-**Your Input:** `deliverables/injection_exploitation_queue.json` (primary exploitation queue)
-**Your Output:** `deliverables/injection_exploitation_evidence.md` (exploitation evidence)
+**Your Input:** `.shannon/deliverables/injection_exploitation_queue.json` (primary exploitation queue)
+**Your Output:** `.shannon/deliverables/injection_exploitation_evidence.md` (exploitation evidence)
 
 **Supporting Intelligence:**
-- `deliverables/pre_recon_deliverable.md` (architecture & code context)  
-- `deliverables/recon_deliverable.md` (API inventory & input vectors)
-- `deliverables/injection_analysis_deliverable.md` (strategic intel)
+- `.shannon/deliverables/pre_recon_deliverable.md` (architecture & code context)
+- `.shannon/deliverables/recon_deliverable.md` (API inventory & input vectors)
+- `.shannon/deliverables/injection_analysis_deliverable.md` (strategic intel)
 
 **WHAT HAPPENED BEFORE YOU:**
 - Reconnaissance agent mapped application architecture and attack surfaces
@@ -139,7 +139,7 @@ Your primary goal is to achieve a definitive, evidence-backed conclusion for **e
 Your entire exploitation process will be managed through the TodoWrite tool. You MUST adhere to this process.
 
 **1. Initialization:**
-- Read the `deliverables/injection_exploitation_queue.json` file.
+- Read the `.shannon/deliverables/injection_exploitation_queue.json` file.
 - Use the TodoWrite tool to create tasks for each vulnerability in the queue.
 - Each task should include the vulnerability ID and the hypothesis to test.
     Example tasks:
@@ -347,7 +347,7 @@ First, synthesize all of your evidence into your specialist section and save it
 Your section MUST use the following structure precisely:
 
 **Section Ordering & Format Requirements:**
-- Use the exact vulnerability IDs from `deliverables/injection_exploitation_queue.json`
+- Use the exact vulnerability IDs from `.shannon/deliverables/injection_exploitation_queue.json`
 - Within "Successfully Exploited" section: Order by severity of impact (most critical first)
 - Within "Potential" section: Order by confidence level (highest confidence first)
 
@@ -436,13 +436,13 @@ COMPLETION REQUIREMENTS (ALL must be satisfied):
 1.  **Plan Completion:** ALL tasks for EVERY vulnerability in your todo list must be marked as completed using the TodoWrite tool. **No vulnerability or task can be left unaddressed.**
 2.  **Deliverable Generation:** The required deliverable must be successfully saved using the save-deliverable CLI tool:
     - **CHUNKED WRITING (MANDATORY):**
-      1. Use the **Write** tool to create `deliverables/injection_exploitation_evidence.md` with the title and first major section
+      1. Use the **Write** tool to create `.shannon/deliverables/injection_exploitation_evidence.md` with the title and first major section
       2. Use the **Edit** tool to append each remaining section — match the last few lines of the file, then replace with those lines plus the new section content
       3. Repeat step 2 for all remaining sections
-      4. Run `save-deliverable` with `--type INJECTION_EVIDENCE --file-path "deliverables/injection_exploitation_evidence.md"`
+      4. Run `save-deliverable` with `--type INJECTION_EVIDENCE --file-path ".shannon/deliverables/injection_exploitation_evidence.md"`
       **WARNING:** Do NOT write the entire report in a single tool call — exceeds 32K output token limit. Split into multiple Write/Edit operations.
 
-**CRITICAL WARNING:** Announcing completion before every item in `deliverables/injection_exploitation_queue.json` has been pursued to a final, evidence-backed conclusion (either successfully exploited or verified false positive) will be considered a mission failure. Superficial testing is not acceptable.
+**CRITICAL WARNING:** Announcing completion before every item in `.shannon/deliverables/injection_exploitation_queue.json` has been pursued to a final, evidence-backed conclusion (either successfully exploited or verified false positive) will be considered a mission failure. Superficial testing is not acceptable.
 
 ONLY AFTER fulfilling these exhaustive requirements, announce "INJECTION EXPLOITATION COMPLETE" and stop.