Extract shared mail routing and IMAP folder helpers

Prompt since previous commit: execute step 1

Centralized route targets, source-folder policy, and modified UTF-7 mailbox quoting. Verification: py_compile, route/folder consistency, and git diff --check passed.

restart_prompt.md

@@ -22,8 +22,6 @@ Git workflow:
 - Work should continue on `codex` unless the user says otherwise.
 - Follow the user’s global workflow: initialize Git when needed, branch before work in existing repos, and commit after each user-prompted change using the required three-section commit message format.
 
-Tracked files include Python scripts, generated reports, logs, caches, and project docs.
-
 Ignored local data includes:
 
 - `mailbox/`
@@ -58,28 +56,58 @@ Sieve:
 - Sieve deployment is not viable with the provider.
 - Future work should move operational automation to Python over IMAP/SMTP.
 
-## Important Current Implementation Notes
+## Current Implementation Notes
 
-`verplaats_bestaand.py` has already been changed so:
+Shared modules:
+
+- `imap_utils.py` centralizes IMAP modified UTF-7 folder encoding/decoding, quoted mailbox names, LIST parsing, and folder listing.
+- `mail_routes.py` centralizes `PREFIX`, domain routes, invoice keywords, source-folder exclusions, already-sorted folders, invoice quarter routing, and generated destination folders.
+
+Scripts using shared IMAP folder handling:
+
+- `verplaats_bestaand.py`
+- `maak_mappen.py`
+- `kopieer_naar_backup.py`
+- `download_mailbox.py`
+- `dagelijks_overzicht.py`
+
+`verplaats_bestaand.py` current behavior:
 
 - `MAP_RENAMES` is intentionally empty.
-- Source folders are selected by `list_source_folders()`.
-- Excluded source folders are `Sent`, `Drafts`, `Trash`, and `Spam`, with both bare and `INBOX.` names where relevant.
-- `ALREADY_SORTED_FOLDERS = {"INBOX.Facturen - verwerkt"}`.
+- Source folders are selected by shared `list_folders()` plus `mail_routes.is_source_folder()`.
 - Step 2 routes all eligible source folders, not just `INBOX`.
-- Move success now requires both `UID COPY` and `UID STORE +FLAGS \Deleted` to return `OK`.
+- Move success requires both `UID COPY` and `UID STORE +FLAGS \Deleted` to return `OK`.
 - Step 3 no longer treats `INBOX.Facturen - verwerkt` as a source.
+- IMAP mailbox names are consistently quoted and encoded through `imap_utils.quote_mailbox()`.
 
-`maak_mappen.py` has already been changed so:
+`maak_mappen.py` current behavior:
 
+- Destination folders are generated from `mail_routes.destination_folders()`.
 - It no longer creates `Archief.*` destination folders.
-- It creates `Technisch` and `Technisch.DMARC`.
+- It creates all parent folders needed for route targets, including `Technisch` and `Technisch.DMARC`.
+- IMAP mailbox names are consistently quoted and encoded through `imap_utils.quote_mailbox()`.
 
-Last verification performed:
+`kopieer_naar_backup.py` current behavior:
+
+- Mirrors folders from one configured IMAP account to another.
+- Skips `INBOX.Trash` and `INBOX.Spam`.
+- Deduplicates by `Message-ID` within each destination folder.
+- Uses shared folder listing and mailbox quoting/encoding for select/create/append operations.
+
+## Last Verification
+
+The latest verification performed:
 
 - `python3 -m py_compile *.py`
-- route/folder consistency check reported `missing_targets 0`
-- archive target check reported `archief_targets 0`
+- `python3 -c 'from mail_routes import DOMAIN_ROUTES,destination_folders; targets={target for _, target in DOMAIN_ROUTES}; folders=set(destination_folders()); print("routes", len(targets)); print("folders", len(folders)); print("missing_targets", sorted(targets-folders)); print("archief_targets", sorted(t for t in targets if t.startswith("Archief") or ".Archief" in t))'`
+- `git diff --check`
+
+Expected consistency result:
+
+- `routes 72`
+- `folders 127`
+- `missing_targets []`
+- `archief_targets []`
 
 ## Reports and Findings
 
@@ -96,32 +124,24 @@ Key earlier findings:
 
 Recommended next work:
 
-1. Refactor shared IMAP utilities:
-   - folder list parsing
-   - mUTF-7 encoding/decoding
-   - folder creation
-   - UID fetch
-   - safe copy/delete/expunge
-   - Message-ID dedupe
+1. Harden move and mirror auditability:
+   - `kopieer_naar_backup.py` should not mark a folder complete if append failures occur.
+   - `verplaats_bestaand.py` should log failures with source folder, UID, destination, and server response.
+   - Add a dry-run audit mode showing planned moves by source and destination.
 
-2. Refactor shared routing logic:
-   - extract the route table from `verplaats_bestaand.py`
-   - support both historical sorting and live sorting from one source of truth
-   - preserve invoice priority and quarter-folder routing
+2. Add shared operation helpers where useful:
+   - UID fetch wrappers.
+   - safe copy/delete/expunge helper.
+   - Message-ID dedupe helper reused by live automation.
 
-3. Harden scripts:
-   - `kopieer_naar_backup.py` should not mark a folder complete if append failures occur
-   - `verplaats_bestaand.py` should log failures with source folder, UID, destination, and server response
-   - add a dry-run audit mode showing planned moves by source and destination
-
-4. Add VPS automation:
+3. Add VPS automation:
    - create an IMAP IDLE daemon for `backup@australius.nl`
    - deploy via SSH to `vps.australius.nl`
    - use a non-root sudo user
    - install as a systemd service
    - keep secrets in an ignored `config.json` with restrictive permissions
 
-5. Test on `backup@australius.nl` before production:
+4. Test on `backup@australius.nl` before production:
    - mirror production mail into backup
    - create target folders in backup
    - run dry-run sorter on backup
@@ -131,4 +151,3 @@ Recommended next work:
 ## Persistent File Rule
 
 Before every future commit in this project, rewrite this `restart_prompt.md` file so it describes the current state at that commit. Do not append. Replace the content with a fresh, accurate reconstruction prompt.
-