### What problem does this PR solve?
##### Problem Description
When parsing HTML files, some page content may be lost.
For example, text inside nested `<font>` tags within multiple `<div>`
elements (e.g.,
`<div><font>Text_1</font></div><div><font>Text_2</font></div>`) fails to
be preserved correctly.
###### Root Cause #1: Block ID propagation is interrupted
1. **Block ID generation**: When the parser encounters a `<div>`, it
generates a new `block_id` because `<div>` belongs to `BLOCK_TAGS`.
2. **Recursive processing**: This `block_id` is passed down recursively
to process the `<div>`’s child nodes.
3. **Interruption occurs**: When processing a child `<font>` tag, the
code enters the `else` branch of `read_text_recursively` (since `<font>`
is a Tag).
4. **Bug location**: The first line in this `else` branch explicitly
sets **`block_id = None`**.
- This discards the valid `block_id` inherited from the parent `<div>`.
- Since `<font>` is not in `BLOCK_TAGS`, it does not generate a new
`block_id`, so it passes `None` to its child text nodes.
5. **Consequence**: The extracted text nodes have an empty `block_id` in
their `metadata`. During the subsequent `merge_block_text` step, these
texts cannot be correctly associated with their original `<div>` block
due to the missing ID. As a result, all text from `<font>` tags gets
merged together, which then triggers a second issue during
concatenation.
6. **Solution:** Remove the forced reset of `block_id` to `None`. When
the current tag (e.g., `<font>`) is not a block-level element, it should
inherit the `block_id` passed down from its parent. This ensures
consistent ownership across the hierarchy: `div` → `font` → `text`.
###### Root Cause #2: Data loss during text concatenation
1. The line `current_content += (" " if current_content else "" +
content)` has a misplaced parenthesis. When `current_content` is
non-empty (`True`):
- The ternary expression evaluates to `" "` (a single space).
- The code executes `current_content += " "`.
- **Result**: Only a space is appended—**the new `content` string is
completely discarded**.
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
8c28587821