Decouple mautrix-meta-instagram from mautrix-meta-messenger and fix Instagram self-building

Since mautrix-meta v26.07, Instagram is a separate bridge upstream (its own binary, container image and configuration schema). As of v0.2608.0, the bridge no longer has a `mode` configuration option at all, so the premise of auto-generating the Instagram role from the Messenger one (one binary, one schema, a mode switch) is gone.

- Drop the role generator (`bin/rebuild-mautrix-meta-instagram.sh` and the `just rebuild-mautrix-meta-instagram` recipe). The two roles are now maintained independently.

- Drop `matrix_bridge_mautrix_meta_instagram_meta_mode` and all mode-derived lookups from the Instagram role. Computed values are unchanged.

- Sync both config templates with the v0.2608.0 example configs: the Instagram template loses `mode` and gains the Instagram-only options; the Messenger template replaces `mode` with the new `tor` option (still derived from `matrix_bridge_mautrix_meta_messenger_meta_mode: facebook-tor`) and loses the Instagram-only `disable_xma_*` options.

- Fix self-building for the Instagram role: build via `Dockerfile.ig` (producing the actual Instagram binary at `/usr/bin/mautrix-instagram`) instead of the Messenger `Dockerfile`. A new `matrix_bridge_mautrix_meta_instagram_container_binary_path` variable points the systemd service at the right binary for self-built and prebuilt images.

- Rename the systemd service templates to role-specific file names.

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/5510

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/configuring-playbook-bridge-mautrix-meta-instagram.md

@@ -13,7 +13,7 @@ The playbook can install and configure the [mautrix-meta](https://github.com/mau
 
 See the project's [documentation](https://docs.mau.fi/bridges/go/meta/index.html) to learn what it does and why it might be useful to you.
 
-Since this bridge component can bridge to both [Messenger](https://messenger.com/) and [Instagram](https://instagram.com/) and you may wish to do both at the same time, the playbook makes it available via 2 different Ansible roles (`matrix-bridge-mautrix-meta-messenger` and `matrix-bridge-mautrix-meta-instagram`). The latter is a reconfigured copy of the first one (created by `just rebuild-mautrix-meta-instagram` and `bin/rebuild-mautrix-meta-instagram.sh`).
+The mautrix-meta project provides bridging to both [Messenger](https://messenger.com/) and [Instagram](https://instagram.com/), each via a separate bridge (its own binary and container image) since mautrix-meta v26.07. The playbook makes them available via 2 different Ansible roles (`matrix-bridge-mautrix-meta-messenger` and `matrix-bridge-mautrix-meta-instagram`), which can both be enabled at the same time.
 
 This documentation page only deals with the bridge's ability to bridge to Instagram. For bridging to Facebook/Messenger, see [Setting up Messenger bridging via Mautrix Meta](configuring-playbook-bridge-mautrix-meta-messenger.md).
 

docs/configuring-playbook-bridge-mautrix-meta-messenger.md

@@ -14,7 +14,7 @@ The playbook can install and configure the [mautrix-meta](https://github.com/mau
 
 See the project's [documentation](https://docs.mau.fi/bridges/go/meta/index.html) to learn what it does and why it might be useful to you.
 
-Since this bridge component can bridge to both [Messenger](https://messenger.com/) and [Instagram](https://instagram.com/) and you may wish to do both at the same time, the playbook makes it available via 2 different Ansible roles (`matrix-bridge-mautrix-meta-messenger` and `matrix-bridge-mautrix-meta-instagram`). The latter is a reconfigured copy of the first one (created by `just rebuild-mautrix-meta-instagram` and `bin/rebuild-mautrix-meta-instagram.sh`).
+The mautrix-meta project provides bridging to both [Messenger](https://messenger.com/) and [Instagram](https://instagram.com/), each via a separate bridge (its own binary and container image) since mautrix-meta v26.07. The playbook makes them available via 2 different Ansible roles (`matrix-bridge-mautrix-meta-messenger` and `matrix-bridge-mautrix-meta-instagram`), which can both be enabled at the same time.
 
 This documentation page only deals with the bridge's ability to bridge to Facebook Messenger. For bridging to Instagram, see [Setting up Instagram bridging via Mautrix Meta](configuring-playbook-bridge-mautrix-meta-instagram.md).