Libmagic version 0.46 (currently available in Debian Trixie/Forky and Ubuntu Resolute) introduced a regression regarding ZIP file detection. While it correctly identifies a ZIP file when reading directly from a file path, it fails when reading the exact same content from a buffer, returning a generic 'application/octet-stream' instead.

Because `guess_mimetype` primarily evaluates buffers, this upstream bug breaks MIME type detection for ZIP files (and related formats like docx, xlsx, etc.) in Odoo environments running this libmagic version.

Since we cannot directly fix the library itself, this commit adapts Odoo's `guess_mimetype` to fallback to our custom implementation when libmagic returns the generic 'application/octet-stream' to workaround this library's bug.

Upstream libmagic fixes:
- https://github.com/file/file/commit/f1adef05b8a85be50d28965b1fd21fcceacf7a4e
- https://github.com/file/file/commit/60b2032b96fc185b37fb0f2152e834efb2edad6e

Upstream python-magic issue:
- https://github.com/ahupp/python-magic/issues/354

runbot-938197

Forward-Port-Of: odoo/odoo#269506

Problem:
- `s_three_columns` is not rendered correctly in Outlook Desktop when the equal-height option is enabled.
- Button padding, border radius, and background color are not rendered properly in Outlook Desktop.

Solution:
- Set the `height` attribute on `td.card-body` along with `valign` so columns keep the same height in Outlook Desktop.
- Use `v:roundrect` to support rounded corners (`arcsize`) and background colors (`fillcolor`), making buttons render consistently with the editor in Outlook Desktop.

Before:
<img width="1249" height="1297" alt="image" src="https://github.com/user-attachments/assets/828bc42b-1e21-404c-a5ae-81d4ee688802" />
After:
<img width="1249" height="1309" alt="image" src="https://github.com/user-attachments/assets/263a1c30-fe86-4e40-b3c2-476abc2bf84a" />

Steps to reproduce:
- Add the `s_three_columns` snippet with one card containing more content than the others.
- Add some buttons.
- Send or preview the email in Outlook Desktop.
- Observe that column heights and button styling are not rendered correctly.

opw-6044725

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Forward-Port-Of: odoo/odoo#269791
Forward-Port-Of: odoo/odoo#269274

**Problem:**
On the /shop page, the "Fill" option in the web editor (cover/contain toggle on product card images) appears clickable but has no visible effect on the product thumbnails.

**Steps to reproduce:**
1. Install website_sale and open /shop.
2. Open the web editor and select the shop page.
3. Locate the "Fill" button group in the right panel (with the two svg icons).
4. Click the alternate option to switch between cover and contain.
5. Observe that the product card thumbnails do not change appearance.

**Current behavior:**
The toggle flips the `o_wsale_context_thumb_cover` class on the products table (and the activation of the `products_thumb_cover` view), but the product images keep rendering with `object-fit: contain` regardless of the toggle state.

**Expected behavior:**
The image fill mode follows the toggle:
- "cover" option active   → product image uses `object-fit: cover`
- "cover" option inactive → product image uses `object-fit: contain`

**Cause of the issue:**
The product image template renders the img with the `object-fit-contain` utility class, and the local SCSS rule declares
`.object-fit-contain { object-fit: contain !important; }`. The CSS variable `--o-wsale-card-thumb-fill-mode` (set to `cover` by `.o_wsale_context_thumb_cover`) does cascade down to the img, but the non-variable, `!important` rule on the utility class always wins, so the variable-driven rule
`object-fit: var(--o-wsale-card-thumb-fill-mode, contain)` is silently overridden and the toggle becomes inert.

**Fix:**
Making the `.object-fit-contain` rule read the same CSS variable lets the existing toggle mechanism take effect without changing any template or removing the utility class. Outside the `.o_wsale_context_thumb_cover` context the variable is undefined, so the `var(..., contain)` fallback preserves the prior `contain` behavior for any other consumer of the class. This keeps the change to a single SCSS line, with no XML touched and no other CSS class semantics altered.

opw-6231432

Forward-Port-Of: odoo/odoo#268302
Forward-Port-Of: odoo/odoo#266717

PostgreSQL's `unaccent` function must be marked as `IMMUTABLE` before it can be used in a functional index.

The ORM usually handles this when the `unaccent` extension is missing and `odoo-bin` is started with the `--unaccent` flag during database creation.
However, it is also possible to start `odoo-bin` with an existing database where the `unaccent` extension is already installed, but the function was never marked as `IMMUTABLE`.

In that case, `unaccent` can still be used in conditions such as `WHERE` clauses, but it cannot be used in functional indexes.

`has_unaccent()` actually has three possible states:
```py
class FunctionStatus(IntEnum):
    MISSING = 0    # function is not present (falsy)
    PRESENT = 1    # function is present but not indexable (not immutable)
    INDEXABLE = 2  # function is present and indexable (immutable)
```
Therefore, checking only `if has_unaccent()` before creating an index using `unaccent` is not enough. The index should only be created when `has_unaccent()` returns `FunctionStatus.INDEXABLE`.

task-6307060

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