⚡️(backend) send recording notification emails from a Celery task

Emails were rendered and sent inline in the LiveKit webhook, so a
slow SMTP server blocked the request and a transient failure lost
the email. Delivery now runs in a worker, with retries and backoff.

The task is generic (template, subject, recipients, context,
language) so other emails can reuse it. The subject is translated
in the worker, and dates are formatted per owner before queuing,
so the arguments stay JSON-serializable.

Without Celery, the task still runs synchronously. Success now
means "queued", not "delivered".

.github/workflows/ci.yml

@@ -87,7 +87,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6.1.0
         with:
           persist-credentials: false
 
@@ -117,11 +117,11 @@ jobs:
           timeout 30 sh -c 'until docker exec garage /garage health; do sleep 1; done'
 
       - name: Install Python
-        uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97 # v7.0.0
+        uses: actions/setup-python@ece7cb06caefa5fff74198d8649806c4678c61a1 # v6.3.0
         with:
-          python-version: "3.14"
+          python-version: "3.13"
       - name: Install uv
-        uses: astral-sh/setup-uv@c18668ad3cf93ea998bef934396af7bb5c839dc7 # v10.2.0
+        uses: astral-sh/setup-uv@37802adc94f370d6bfd71619e3f0bf239e1f3b78 # v7.6.0
       - name: Install the dependencies
         run: uv sync --locked --all-extras
 
@@ -160,7 +160,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6.1.0
         with:
           persist-credentials: false
 
@@ -170,12 +170,12 @@ jobs:
           sudo apt-get install -y ffmpeg
 
       - name: Install Python
-        uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97 # v7.0.0
+        uses: actions/setup-python@ece7cb06caefa5fff74198d8649806c4678c61a1 # v6.3.0
         with:
-          python-version: "3.14"
+          python-version: "3.13"
 
       - name: Install uv
-        uses: astral-sh/setup-uv@c18668ad3cf93ea998bef934396af7bb5c839dc7 # v10.2.0
+        uses: astral-sh/setup-uv@37802adc94f370d6bfd71619e3f0bf239e1f3b78 # v7.6.0
 
       - name: Install the project
         run: uv sync --locked --all-extras
@@ -189,7 +189,7 @@ jobs:
       contents: read
     steps:
       - name: Checkout repository
-        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6.1.0
         with:
           persist-credentials: false
 
@@ -208,12 +208,12 @@ jobs:
       contents: read
     steps:
       - name: Checkout repository
-        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6.1.0
         with:
           persist-credentials: false
 
       - name: Install Node.js
-        uses: actions/setup-node@820762786026740c76f36085b0efc47a31fe5020 # v7.0.0
+        uses: actions/setup-node@249970729cb0ef3589644e2896645e5dc5ba9c38 # v6.5.0
         with:
           node-version: "24"
 
@@ -232,7 +232,7 @@ jobs:
         working-directory: src/sdk/library
     steps:
       - name: Checkout repository
-        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6.1.0
         with:
           persist-credentials: false
 
@@ -255,7 +255,7 @@ jobs:
         working-directory: src/sdk/library
     steps:
       - name: Checkout repository
-        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6.1.0
         with:
           persist-credentials: false
 

.gitlint

@@ -22,9 +22,6 @@
 # See http://jorisroovers.github.io/gitlint/user_defined_rules for details
 extra-path=gitlint/
 
-# Use "search" semantics for regexes (gitlint's future default)
-regex-style-search=True
-
 # [title-max-length]
 # line-length=80